Benign prostatic hyperplasia (BPH) and prostate cancer are common conditions in the older male population. For people with BPH, the enlarged prostate can compress the urethra causing obstruction of the urine pathway, which results in difficulty urinating. The enlarged prostate can also cause urethral stones, inflammation, infection and in some instances, kidney failure.
Major treatment methods for BPH include surgical treatment such as a prostatectomy or transurethral resection of the prostate. These treatments require the patient to be hospitalized, which can be a financial burden to the patient. Additionally, surgical procedures can result in significant side effects such as bleeding, infection, residual urethral obstruction or stricture, retrograde ejaculation, and/or incontinence or impotence. Patients who are too old or who have weak cardiovascular functions are not good candidates for receiving these treatment methods.
Photodynamic treatment (PDT) methods are new methods for treating cancers. In light-activated drug therapy, also known as PDT, light of a specific wavelength or waveband is directed toward a target cell or cells that have been rendered photosensitive through the administration of a photoreactive, photoinitiating, or photosensitizing agent. The drug is commonly administered to the patient via intravenous injection, oral administration, or by local delivery to the treatment site. A light source emitting certain wavelength or waveband can be used to irradiate the cancerous tumor or the enlarged tissue by activating the photosensitizer to produce a strong oxidizing agent that can kill the cancerous tumor or enlarged tissues. As compared to surgical alternatives, the light-activated drug therapy is minimally invasive, less costly, and has a lower risk of complications.
One type of light delivery system used for light-activated drug therapy comprises the delivery of light from a light source, such as a laser, to the targeted cells using an optical fiber delivery system with special light-diffusing tips on the fibers. This type of light delivery system may further include optical fiber cylindrical diffusers, spherical diffusers, micro-lensing systems, an over-the-wire cylindrical diffusing multi-optical fiber catheter, and a light-diffusing optical fiber guide wire. This light delivery system generally employs a remotely located high-powered laser, or solid-state laser diode array, coupled to optical fibers for delivery of the light to the targeted cells.
The light source for the light delivery system used for light-activated drug therapy may also be light emitting diodes (LEDs) or solid-state laser diodes (LDs). LEDs or LDs may be arrayed in an elongated device to form a “light bar” for the light delivery system. The LEDs or LDs may be either wire bonded or electrically coupled utilizing a “flip chip” technique that is used in arranging other types of semiconductor chips on a conductive substrate. Various arrangements and configurations of LEDs or LDs are described in U.S. Pat. Nos. 5,445,608; 6,958,498; 6,784,460; and 6,445,011, which are incorporated herein by reference.
One of the challenges in design and production of light bars relates to size. The largest diameter of the light bar is defined by human anatomy and the smallest diameter is defined by the size of the light emitters that emit light of a desired wavelength or waveband at a sufficient energy level, and the fragility of the bar as its thickness is reduced, which increases the risk of breaking in the patient.
Presently, there exists a need for an apparatus for light-activated drug therapy for effectively treating prostate via the urethra that is cost effective, less invasive than other treatments, and has less risk of complications. Accordingly, there is a need for smaller LEDs or LDs and other light sources that are safe for use in a urethra tract introduced via a catheter-like device.